Surgical stapler having an articulation mechanism

ABSTRACT

An articulation mechanism for use with a surgical instrument includes a shaft, a first member disposed in mechanical cooperation with the articulation shaft, a second member disposed in mechanical cooperation with the shaft, and a flexible shaft having proximal and distal portions. The flexible member is operatively coupled to the first and second members. Upon rotation of the articulation shaft, at least one of the first and the second members moves longitudinally with respect to the other of the first and second members between a first position where the first and second members are approximated to each other and a second position where the first and second members are spaced apart from each other. This longitudinal motion causes the distal portion of the flexible member to articulate relative to the proximal portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/047,908, filed on Mar. 15, 2011, now U.S. Pat. No. 8,292,147, whichis a divisional of U.S. application Ser. No. 12/244,797, filed on Oct.3, 2008, now U.S. Pat. No. 7,909,220, which claims priority to and thebenefit of U.S. Provisional Patent Application Ser. No. 60/997,775,filed on Oct. 5, 2007, the entire contents of which are hereinincorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to apparatus and methods for surgicalprocedures. More particularly, the present disclosure relates to asurgical stapler and an articulation mechanism for use therewith.

2. Description of Related Art

Surgical instruments for fastening tissue are well known. Some surgicalfastening devices first clamp tissue between opposing jaw structures andthen join them with surgical fasteners. Several kinds of surgicalinstruments are specifically adapted for use in various procedures suchas end-to-end anastomosis, endoscopic gastrointestinal anastomosis,transverse anastomosis, among others. U.S. Pat. Nos. 5,915,616;6,202,914; 5,865,361; and 5,964,394 describe examples of surgicalfastening instruments. Although these surgical fastening instrumentstypically employ surgical staples, other kinds of fasteners, such astwo-part polymeric fasteners, may be used.

Surgical fastening instruments typically include two opposing jawstructures adapted to capture tissue. One jaw structure usually containsa staple cartridge housing a plurality of staples. The staples may bearranged in a single row or a plurality of rows. The other jaw structurehas an anvil that defines a surface for forming the staple legs as thestaples are driven from the staple cartridge. The surgical fasteninginstruments also include one or more cam members configured to effectthe stapling operation. During use, the cam members act upon staplepushers and eject the staples either sequentially or simultaneously fromthe staple cartridge. The staple cartridge may include a knife adaptedto cut or open the stapled tissue between the rows of staples. U.S. Pat.Nos. 3,079,606 and 3,490,675 disclose examples of this kind ofinstrument.

Certain surgical fastening instruments include articulating mechanismsto articulate a tool assembly or an end effector. An articulationmechanism may have an articulation actuator, a plurality of pulleys, anda plurality of articulation cables. The articulation actuator isoperatively coupled to the articulation cables, and a portion of eacharticulation cable is disposed in a corresponding pulley. In operation,the articulation cables move longitudinally in proximal and distaldirections upon actuation of the articulation actuator. As thearticulation cables move longitudinally, the pulleys rotate and movementof the articulation cables causes articulation of the end effector. U.S.Patent Application Serial No. 2007/0108252, which is assigned to U.S.Surgical, a division of Tyco Healthcare Group LP and is herebyincorporated by reference in its entirety, describes an example of thiskind of articulation mechanism.

SUMMARY

The present disclosure relates to an articulation mechanism for use witha surgical instrument. This articulation mechanism includes a shaft, afirst member disposed in mechanical cooperation with the articulationshaft, a second member disposed in mechanical cooperation with theshaft, and a flexible shaft having proximal and distal portions. Theflexible member is operatively coupled to the first and second members.Upon rotation of the articulation shaft, at least one of the first andthe second members moves longitudinally with respect to the other of thefirst and second members between a first position where the first andsecond members are approximated to each other and a second positionwhere the first and second members are spaced apart from each other.This longitudinal motion causes the distal portion of the flexiblemember to articulate relative to the proximal portion.

The present disclosure also relates to a surgical fastening instrumentincluding a flexible shaft and a nutating gear drive operativelyconnected to the flexible shaft. The nutating gear is configured toreduce the speed and increase the torque potential of the flexibleshaft. The surgical fastening instrument further includes a drive shaftconfigured to be selectively attached to the nutating gear drive.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the presently disclosed surgical stapler are describedherein with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a surgical instrument according to anembodiment of the present disclosure;

FIG. 2 is a side view of the surgical instrument of FIG. 1;

FIG. 3 is an top view of the surgical instrument of FIG. 1, showingarticulation of a flexible member;

FIG. 4 is a perspective view of the surgical instrument of FIG. 1connected to an actuation apparatus and a motor assembly;

FIG. 5 is a perspective exploded view of the surgical instrument of FIG.1;

FIG. 6 is a front perspective view of a clamp cam;

FIG. 7 is a rear perspective view of the clamp cam of FIG. 6;

FIG. 8 is a perspective view of a crown stator;

FIG. 8A is a perspective view of a drive shaft;

FIG. 8B is an enlarged perspective view of a distal portion of the driveshaft of FIG. 8A;

FIG. 9 is a front view of a wobbler;

FIG. 10 is a side view of the wobbler of FIG. 9;

FIG. 11 is a rear perspective view of the wobbler of FIG. 9;

FIG. 12 is a bottom perspective view of a transition member, a nutatinggear drive, and a tool assembly of the surgical instrument of FIG. 1;

FIG. 13 is a front cross-sectional view of the tool assembly taken alongsection line 13-13 of FIG. 2;

FIG. 14 is perspective view of the distal end of the flexible member ofthe surgical instrument of FIG. 1 illustrating a nutating gear drive;

FIG. 15 is a perspective view of the distal end of the flexible memberof FIG. 14 showing a pinion gear separated from a drive shaft;

FIG. 16 is a perspective view of the distal end of the flexible memberof FIG. 14 showing a wobbler and the drive shaft;

FIG. 17 is a perspective view of the distal end of the flexible memberwith the drive shaft removed;

FIG. 18 is a perspective cross-sectional view of the transition member,the nutating gear drive, and the clamp cam of the surgical instrument ofFIG. 1;

FIG. 19 is a side cross-sectional view of the surgical instrument ofFIG. 1;

FIG. 20 is a side cross-sectional view of the transition member, thenutating gear drive, and the clamp cam taken around section 20 of FIG.19;

FIG. 21 is a side cross-sectional view of the tool assembly, the clampcam, and the nutating gear drive taken along section line 21-21 of FIG.3;

FIG. 22 is a perspective view of the nutating gear drive and the toolassembly of the surgical instrument of FIG. 1, showing a lower portionof the crown stator engaging a crown gear;

FIG. 23 is a perspective view of the nutating gear drive and the toolassembly of the surgical instrument of FIG. 1, showing an upper portionof the crown stator engaging the crown gear;

FIG. 24 is a side cross-sectional view of the tool assembly of thesurgical instrument of FIG. 1, showing the a long lead screw, a clampcam, and a nutating gear drive;

FIG. 25 is a side cross-sectional view of the tool assembly of thesurgical instrument of FIG. 1, showing an actuation sled engagingpushers;

FIG. 26 is a cross-sectional side view the nutating gear drive and thetransition member taken around section 26 of FIG. 25;

FIG. 27 is a perspective view of a second and third pinion gears takenaround section 27 of FIG. 12;

FIG. 28 is a side perspective view of an articulation mechanismaccording to an embodiment of the present disclosure;

FIG. 29 is a exploded perspective view of the articulation mechanism ofFIG. 28;

FIG. 30 is a side perspective view of the articulation mechanism of FIG.28, showing a first rotating member and a second rotating member movingaway from each other;

FIG. 31 is a side perspective view of the articulation mechanism of FIG.28, showing the first rotating member and the second rotating membermoving toward each other;

FIG. 32 is a side perspective view of a handle assembly according to anembodiment of the present disclosure;

FIG. 33 is a perspective cut away view of the handle assembly of FIG.32, showing an articulation mechanism, a motor, and a power source; and

FIG. 34 is a rear cross-sectional view of the handle assembly of FIG. 32with the articulation mechanism of FIG. 28 disposed therein, taken alongsection line 34-34 of FIG. 33.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the presently disclosed surgical instrument will now bedescribed in detail with reference to the drawings wherein likereference numerals identify similar or identical elements. In thedrawings and in the description that follows, the term “proximal,” as istraditional, will refer to the end of the surgical instrument that isclosest to the operator, while the term “distal” will refer to the endof the surgical instrument that is farthest from the operator.

Referring to FIGS. 1-3, a surgical instrument is generally designated as100. Surgical instrument 100 includes a flexible member 110 and a toolassembly 120. Flexible member 110 is at least partially formed from aplurality of generally wedge shaped sections 110 a. Wedge shapedsections 110 a are spaced apart from one another. When flexible member110 is in a first state (FIG. 2), a first distance exists between wedgesections 110 a. As flexible member 110 is repositioned from the firststate toward a second state (FIG. 3), the distance between wedgesections 110 a on at least one side of flexible member 110 increases.Wedge sections 110 a have a wedge shape, but other shapes are alsocontemplated.

Tool assembly 120 is operatively coupled to flexible member 110 andincludes a support member 101, a cartridge 107, and an anvil 192.Support member 101 has a proximal body portion 101 a and a distal bodyportion 101 b. Proximal body portion 101 b is connected to a distal endof flexible member 110. Distal body portion 101 b supports cartridge107. It is contemplated that cartridge 107 may be a replaceablecartridge. Anvil 192 is configured to pivot relative to cartridge 107.In addition, anvil 192 has a tissue contacting surface 111 having aplurality of fastener deforming concavities 113. During operation,fastener deforming concavities 113 deform the legs of fasteners driventoward anvil 192 (see FIG. 25). Cartridge 107 also has a tissuecontacting surface 103 and retention slots 105 adapted to receivefasteners. Retention slots 105 may be arranged in longitudinal rows. Inthe depicted embodiment, cartridge 107 includes two longitudinal rows ofretention slots 105 although other arrangements of retention slots 105are within the scope of this disclosure. In operation, fasteners exitthrough retention slots 105 upon actuation of tool assembly 120.

With reference to FIG. 4, surgical instrument 100 is operatively coupledto an actuation apparatus 130 for actuating tool assembly 120. Thepresent disclosure contemplates that any suitable actuation apparatusmay be employed to actuate tool assembly 120. In particular, actuationapparatus 130 is operatively coupled to flexible member 110. A motorassembly 142 is mechanically coupled to actuation apparatus 130.Although the drawings show motor assembly 142 positioned outsideactuation apparatus 130, one skilled in the art will recognize thatmotor assembly 142 may be located within actuation apparatus 130. Motorassembly 142 may be powered by an electric motor or a pneumatic motor.Alternatively, actuation apparatus 130 may be powered by other kinds ofdriving devices including manual actuators. Irrespective of the drivingdevices utilized, actuation apparatus 130 is capable of rotating aflexible shaft 122 (see FIG. 19) partially disposed within flexiblemember 110.

With reference to FIGS. 5 and 18-20, flexible member 110 partiallyretains a transition member 124 at its distal end 110 b. Transitionmember 124 operatively connects flexible member 110 to nutating geardrive 158 and includes a cavity region 150. Cavity region 150 surroundsa coupling 152 adapted for connecting flexible shaft 122 to drive shaft154. Drive shaft 154 includes at least one outwardly extendingprotrusion 155 for engaging a wobbler 164 of nutating gear drive 158(see FIG. 20).

Referring now to FIGS. 9-11, wobbler 164 of nutating gear drive 158includes a tubular portion 160 having lumen 161 extending therethrough.Lumen 161 of tubular body 160 is adapted to receive drive shaft 154 (seeFIG. 20). A pressing portion 163 surrounds tubular body 160 and has aproximal surface 163 a and a distal surface 163 b. Proximal surface 163a is substantially orthogonal to tubular portion 160. In contrast,distal surface 163 b defines an angle with respect to tubular portion160. Additionally, wobbler 164 includes an angled elongate portion 165extending distally from distal surface 163 b. Angled elongate portion165 defines an angle with respect to tubular portion 162 and includes ahollow space 167 (see FIG. 20). Hollow space 167 encompasses a portionof drive shaft 154 and outwardly extending protrusions 155 (see FIG.16). Angled elongate portion 165 also includes an engagement portion 169adapted to engage the outwardly extending protrusions 155 of drive shaft154 (see FIG. 17). During operation, outwardly extending protrusions 155engage engagement portion 169 when drive shaft 154 is moved proximally.Once outwardly extending protrusions 155 engage engagement portion 169,drive shaft 154 drives wobbler 164. In the depicted embodiment,engagement portion 169 is a cross-shaped recess positioned on a proximalsegment of angled elongate portion 165. Nonetheless, one skilled in theart will envision that engagement portion 169 may have any suitableconfiguration so long as it is able to engage outwardly extendingprotrusions 155.

Referring again to FIGS. 5 and 18-20, a first washer 156 surroundstubular portion 160 of wobbler 164 and separates an internal surface 171of transition member 124 from a bearing 173. Bearing 173 also surroundstubular portion 160 of wobbler 164 and separates first washer 156 from asecond washer 157. As seen in FIG. 20, first washer 156 is disposedwithin transition member 124. Bearing 173 is at least partiallypositioned within transition member 124. Second washer 157, however, isjuxtaposed to proximal surface 163 a of pressing portion 163. Distalsurface 163 b of pressing portion 163, in contrast, is disposed injuxtaposed alignment with a crown stator 168.

With reference to FIGS. 8 and 20, crown stator 168 includes a number ofteeth 174, an opening 177, and a pin 175 extending outwardly. Teeth 174face teeth 176 of a crown gear 170, as seen in FIG. 20. In operation,teeth 174 of crown stator 168 mesh with teeth 176 of crown gear 170.Opening 177 of crown stator 168 is adapted to receive angled elongateportion 165 of wobbler 164 (see FIG. 10). Pin 175 of crown stator 168 isslidably positioned in a slot 159 of support member 101. Slot 159 islocated in a lower portion of proximal body portion 101 a of supportmember 101. During operation, pin 175 inhibits the rotation of crownstator 168 while allowing crown stator 168 to wobble. The wobblingmotion of crown stator 168 causes the rotation of crown gear 170.

Referring again to FIGS. 5 and 18-20, crown gear 170 includes a plate178, an elongate body 162, and bore 153 extending therethrough. A numberof teeth 176 protrude proximally from plate 178. Bore 153 extends fromplate 178 to elongate body 162 and is configured to receive a short leadscrew 180. A proximal portion of short lead screw 180 is tightly lockedto crown gear 170. In operation, short lead screw 180 rotates inresponse to a rotation of crown gear 170. A gear cage 188 surroundselongate body 162 of crown gear 170 and is fixed to support member 101.In one embodiment, a screw secures gear cage 188 to support member 101.Gear cage 188 stabilizes crown gear 170 and is positioned adjacent to anE-ring 186. E-ring 186 is disposed in a recess 151 surrounding a distalend 162 b of elongate body 162. Distal end 162 b of elongate body 162also includes a flange 149 to secure E-ring 186. Flange 149 sits on arecess 147 of clamp cam 182 when clamp cam 182 is positioned next tocrown gear 170, as depicted in FIG. 18.

With reference to FIGS. 5-7, clamp cam 182 includes a threaded bore 184adapted to receive short lead screw 180 and at least one contouredsurface 183 configured to receive at least one leg 193 disposed at aproximal portion 192 a of anvil 192. Contoured surfaces 183 have adownward inclination in the proximal direction. During operation, aclockwise rotation of short lead screw 180 moves clamp cam 182proximally through proximal body portion 101 a of support member 101.When clamp cam 182 translates proximally, countered surfaces 193 urgelegs 193 of anvil 192 in an upward direction. As legs 193 move upwardly,a distal portion 192 b of anvil 192 moves toward cartridge 107 to clamptissue.

With reference to FIGS. 5, 8A, 8B, 14, 15 and 20, short lead screw 180includes a central lumen 181 adapted to receive a portion of drive shaft154. A proximal portion 154 a of drive shaft 154 is operativelyconnected to coupling 152, and a distal portion 154 b is configured tobe attached to a first pinion gear 194. In an embodiment, distal portion154 b has a tip 145 and a spline 143. First pinion gear 194 has aplurality of indentations 141 adapted to receive spline 143. When driveshaft 154 is moved distally, spline 143 engages indentations 141 offirst pinion gear 194.

With reference to FIGS. 5, 12, 13, and 18-20, first pinion gear 194meshes simultaneously with second pinion gear 195 and third pinion gear196 when drive shaft 154 is moved distally. Therefore, first pinion gear194 is configured to mesh with second and third pinion gears 195, 196.Second pinion gear 195 is operatively attached to a proximal end 139 aof first long lead screw 139, and third pinion gear 196 is operativelysecured to a proximal end 137 a of a second long lead screw 137. Duringoperation, the rotation of second and third pinion gears 195, 196 causesthe respective rotation of first and second long lead screws 139, 137.First and second long lead screws 139, 137 extend through cartridge 107and are configured to engage an actuation sled 135. As seen in FIG. 13,actuation sled 135 includes two threaded holes 129, 133 for receivingrespective first and second long lead screws 139, 137. In use, thecounterclockwise rotation of first and second long lead screws 139, 137advances actuation sled 135 through cartridge 107.

As discussed above, cartridge 107 includes a plurality of retentionslots 105. Each retention slot 105 holds a pusher 131 and a fastener125. In operation, actuation sled 135 acts upon pushers 131 to eject thefasteners 125 housed in retention slots 105. As fasteners 125 are driventoward anvil 192, fastener deforming concavities 113 deform the legs offasteners 125.

Proximal portion 192 a of anvil 192 is pivotably connected to theproximal body portion 101 a of support member 101. In one embodiment,proximal body portion 101 a has a hole 123 configured to receive a pivotpin 121. Pivot pin 121 pivotably couples support member 101 and anvil192. Consequently, anvil 192 moves from an open position to a clampedposition upon actuation of actuation apparatus 130. In the openposition, anvil 192 is spaced apart from cartridge 107, as seen in FIG.21. In the clamped position, anvil 192 is disposed in juxtaposedalignment with cartridge 107, as shown in FIG. 24.

Surgical instrument 100 is capable of fastening body tissue. Referringnow to FIGS. 20-27, the user places tool assembly 120 in the targetsurgical site. To this end, flexible member 110 may be articulatedmanually or by employing an articulation mechanism. (See FIG. 3).

After properly positioning tool assembly 120 in the desired surgicalsite, the user turns on motor assembly 142 to activate actuationapparatus 130. (See FIG. 4). Utilizing actuation apparatus 130, the usermoves flexible shaft 122 proximally in the direction indicated by arrows“A.” (See FIG. 20). Since flexible shaft 122 is connected to drive shaft154, the proximal translation of flexible shaft 122 moves drive shaft154 proximally. When drive shaft 154 is translated proximally, outwardlyextending protrusions 155 engage in engagement portion 169 of wobbler164, as illustrated in FIG. 20. Once outwardly extending protrusions 155are engaged to engagement portion 169, the user rotates flexible shaft122 to move anvil 192.

Motor assembly 142 drives actuation apparatus 130. Actuation apparatus130 rotates flexible shaft 122 at high speed with a corresponding lowtorque value. The rotary motion of flexible shaft 122 causes therotation of coupling 152 and drive shaft 154. The direction of therotation of flexible shaft 122 ultimately determines the movement ofanvil 192. If an anvil 192 is in an open position, as shown in FIG. 21,the user moves anvil 192 to a clamped position by rotating flexibleshaft 122 in a counterclockwise direction, as indicated by arrows “B.”(See FIGS. 22 and 23). The high speed, low torque rotation of flexibleshaft 122 causes the rotation of drive shaft 154 and wobbler 164. Therotary motion of wobbler 164, in turn, causes crown stator 168 to wobbleback and forth in the direction indicated by arrows “C.” (See FIGS. 22and 23). As crown stator 168 wobbles, only some teeth 174 of crownstator 168 mesh with teeth 176 of crown gear 170. The difference in thenumber of teeth between crown stator 168 and crown gear 170 dictates thespeed reduction ratio of nutating gear drive 158. Specifically, whenwobbler 164 effects one full rotation, crown gear 168 rotates an amountthat is directly proportional to the difference in the number of teethbetween crown stator 168 and crown gear 170.

In general, while crown stator 168 wobbles, crown gear 170 rotatesclockwise at low speed, with a corresponding high torque potential, asindicated by arrows “D. (See FIGS. 22 and 23). The low speed rotationand high torque potential of crown gear 170 causes the rotation of shortlead screw 180. Given that short lead screw 180 is threadably coupled toclamp cam 182, the clockwise rotation of short lead screw 180 movesclamp cam 182 proximally, as indicated by arrows “E.” (See FIGS. 22-24).As clamp cam 182 moves proximally, legs 193 of anvil 192 move upwardlyalong contoured surfaces 183. When legs 193 move in an upward direction,anvil 192 pivots about pivot pin 121, thereby causing the distal portion192 b of anvil 192 to descend and clamp tissue, as indicated by arrows“F.” (See FIGS. 22-24).

In order to eject fasteners 125, the user advances flexible shaft 122 ina distal direction, as indicated by arrows “G.” (See FIGS. 25 and 26).The distal translation of flexible shaft 122 moves drive shaft 154distally. When drive shaft 154 advances in a distal direction, itengages first pinion gear 194 and disengages outwardly extendingprotrusions 155 from engagement portion 169 of wobbler 164. Then, theuser rotates flexible shaft 122 clockwise, as indicated by arrow “H.”(See FIG. 26). As flexible shaft 122 rotates clockwise, drive shaft 154and first pinion gear 194 rotate clockwise, as indicated by arrow “I.”(See FIG. 28). The rotation of first pinion gear 194 causes the rotationof second and third pinion gears 195, 196 in a counterclockwisedirection, as indicated by arrows “J.” (See FIG. 27). While second andthird pinion gears 195, 196 rotate, first and second long lead screws139, 137 rotate, thereby advancing actuation sled 135 distally throughcartridge 107, as indicated by arrow “K.” (See FIG. 25). While movingdistally, actuation sled 135 sequentially contacts pushers 131. Pushers131 then translate vertically within retention slots 105 and ejectfasteners 125. Fastener deforming concavities 113 deform the legs offasteners 125 as the pushers 131 drive fasteners toward anvil 192.Thereafter, the user has the option of moving actuation sled 135proximally by rotating flexible shaft 122 in a counterclockwisedirection.

With reference to FIGS. 28-31, the present disclosure also relates to anarticulation mechanism 200 for use with surgical instrument 100 or anyother suitable surgical device. Generally, articulation mechanism 200includes an articulation shaft 202 having first and second ends 202 a,202 b, a first rotating member 204, a second rotating member 206, and aknob 208 operatively secured to articulation shaft 202. A first cable214 is attached to first rotating member 204, and a second cable 216 issecured to second rotating member 206. First and second cables 214, 216are disposed in mechanical cooperation with a tool assembly or aflexible member such that the combined proximal and distal movements offirst and second cables 214, 216 articulate the tool assembly orflexible member. Although the drawings show cables, one skilled in theart will recognize that articulation mechanism 200 may include anyapparatus capable of steering a tool assembly or a flexible member.First rotating member 204 includes a clearance hole 218 adapted toslidably receive second cable 216. First and second rotating members204, 206 are mounted on articulation shaft 202. Articulation shaft 202includes a right-hand groove 212 and a left-hand groove 210 formedthereon. The grooves 210, 212 have a generally helical configuration. Itis further contemplated that the grooves 210, 212 may have a fixed or avariable pitch along articulation shaft 202. Additionally, raised ribsmay be substituted for the grooves 210, 212.

First rotating member 204 is adapted to engage left-hand groove 210,whereas second rotating member 206 is adapted to engage right-handgroove 212. Each rotating member 204, 206 includes a respective firstand second screws 220, 222 for facilitating engagement with thecorresponding grooves 210, 212 of articulation shaft 202. First rotatingmember 204 has a hole 224 configured to receive first screw 220, andsecond rotating member 206 has a hole 226 adapted to receive secondscrew 222. During operation, first screw 220 engages left-hand groove210, and second screw 222 engages right-hand groove 212. In addition,knob 208 is operatively secured to second end 202 b of articulationshaft 202. It is contemplated that other structures may be included forfacilitating engagement between articulation shaft 202 and the first andsecond rotating members 204, 206. For example, a post or recess may belocated on an interior surface of at least one of first and secondrotating members 204, 206, such that it engages and interacts with therespective groove 210, 212 or rib on articulation shaft 202.

With reference to FIGS. 32-34, in one embodiment, articulation mechanism200 is operatively associated with a handle assembly 300. Though thedrawings show articulation mechanism 200 operatively associated withhandle assembly 300, one skilled in the art will recognize thatarticulation mechanism 200 may be used in conjunction with any suitableactuation apparatus. Handle assembly 300 is configured to rotatearticulation shaft 202 and includes a housing 302, a trigger 304disposed on a handle 316, and an external slit 306 for partiallyreceiving knob 208. Housing 302 encompass a motor 308, a power source310 for energizing motor 308, and articulation mechanism 200. Powersource 310 provides energy to motor 308 upon actuation of trigger 304.Thus, trigger 304 is disposed in electro-mechanical cooperation withmotor 308 and power source 310. Motor 308 includes a transmission shaft312 that extends longitudinally through articulation shaft 202 and isoperatively coupled to flexible shaft 122. (See FIG. 19). Duringoperation, when motor 308 is turned on, transmission shaft 312 rotatesflexible shaft 122, thereby rotating drive shaft 154.

In operation, a user may alternatively rotate articulation shaft 202manually through knob 208. When knob 208 is rotated in a clockwisedirection, articulation shaft 202 rotates clockwise and moves first andsecond rotating members 204, 204 longitudinally away from each other, asindicated by arrows “L” in FIG. 28. This longitudinal motion of firstand second rotating members 204, 206 translates first cable 214 in thedirection indicated by arrow “M” and second cable 216 in the directionindicated by arrow “N.” The combined movement of first and second cables214, 216 articulates a distal portion of any suitable surgicalinstrument.

On the contrary, when knob 208 rotates in a counterclockwise direction,articulation shaft 202 rotates counterclockwise and approximates firstand second rotating members 204, 206 toward each other, as indicated byarrows “O” of FIG. 34. This motion of first and second rotating members204, 206 advances first cable 214 in the direction indicated by arrow“P” and second cable 216 in the direction indicated by arrow “Q.” (SeeFIG. 31). The combined motion of first and second cables 214, 216articulates a distal portion of any suitable surgical instrument.

In one embodiment, housing 302 includes a longitudinal slot 314 adaptedto receive tabs 228, 230 of first and second rotating members 204, 206,as seen in FIG. 34. Tab 228 protrudes from first rotating member 204,whereas tab 230 protrudes from second rotating member 206. Whenarticulation mechanism 200 is positioned inside housing 302, tabs 228,230 are located within longitudinal slot 314 and, during operation,prevent first and second rotating members 204, 206 from rotating asarticulation shaft 202 rotates.

It will be understood that various modifications may be made to theembodiments disclosed herein. For example, articulation mechanism 200may be operatively to any suitable medical instrument or tool other thansurgical instrument 100. Moreover, other driving mechanism, instead ofhandle assembly 300, may drive actuation shaft 202 of articulationmechanism 200. Therefore, the above description should not be construedas limiting, but merely as exemplifications of embodiments. Thoseskilled in the art will envision other modifications within the scopeand spirit of the present disclosure.

What is claimed is:
 1. A surgical instrument comprising: a toolassembly; a drive shaft operatively coupled with the tool assembly; anutating gear drive configured to reduce a speed and increase a torqueof the drive shaft, wherein the drive shaft is transitionable between afirst position in which the drive shaft operatively engages the nutatinggear drive and a second position in which the drive shaft disengages thenutating gear drive.
 2. The surgical instrument according to claim 1,wherein the drive shaft includes an outwardly extending protrusionconfigured to engage the nutating gear drive when the drive shaft is inthe first position.
 3. The surgical instrument according to claim 2,wherein the nutating gear drive includes an engagement portionconfigured to engage the outwardly extending protrusion when the driveshaft is in the first position.
 4. The surgical instrument according toclaim 3, wherein the engagement portion is a cross-shaped recess.
 5. Thesurgical instrument according to claim 2, wherein the tool assemblyincludes an anvil and a cartridge including a plurality of fasteners anda sled configured to drive the plurality of fasteners through tissue andtowards the anvil, wherein the anvil and the cartridge are movablerelative to each other between spaced and approximated positions.
 6. Thesurgical instrument according to claim 5, wherein rotation of the driveshaft in the first position moves the anvil and the cartridge relativeto each other between the spaced and approximated positions.
 7. Thesurgical instrument according to claim 5, wherein rotation of the driveshaft in the second position drives the sled within the cartridge. 8.The surgical instrument according to claim 5, wherein the tool assemblyincludes first and second lead screws, the first lead screw operativelycoupled with at least one of the anvil or the cartridge, whereinrotation of the first lead screw moves the at least one of the anvil orthe cartridge relative to the other of the at least one anvil orcartridge.
 9. The surgical instrument according to claim 8, wherein thesecond lead screw is operatively coupled with the sled, wherein rotationof the second lead screw causes translation of the sled within thecartridge.
 10. The surgical instrument according to claim 1, furthercomprising a motor operatively coupled with the drive shaft.
 11. Thesurgical instrument according to claim 1, wherein the nutating geardrive includes a wobbler having a tubular portion having a lumenconfigured to receive the drive shaft therethrough, a proximal surfacesubstantially orthogonal to the tubular portion, and a distal surfacedefining an acute angle with respect to the proximal surface.
 12. Thesurgical instrument according to claim 11, wherein the wobbler includesan angled elongate portion extending distally from the distal surface,the angled elongate portion defining a hollow space configured toreceive at least a portion of the drive shaft and including anengagement portion configured to securely engage the protrusion of thedrive shaft when the drive shaft is in the first position.
 13. Thesurgical instrument according to claim 11, wherein the nutating geardrive further includes a crown gear and a crown stator operativelyengaging the wobbler and configured to mesh with the crown gear when thedrive shaft is in the first position, wherein rotation of the wobblercauses wobbling motion of the crown stator which in turn causes rotationof the crown gear, thereby moving the anvil and the cartridge relativeto each other between the spaced and approximated positions.